1. Field of the Invention
This invention relates to a pneumatic marine fender composed of a cylindrical barrel serving as a shock receiving face and a method of manufacturing the same.
2. Description of the Prior Art
The above mentioned kind of pneumatic marine fender composed of a cylindrical barrel consists of a hollow cylindrical shell. The cylindrical barrel is inflated by applying an internal pressure therein and fitted to a ship's side or quay and floated on the sea for the purpose of absorbing the dynamic energy arising during the contact between two ships or during the berthing of a ship on being moored to a floating body or quay. Such pneumatic marine fender makes use of its cylindrical barrel of the hollow cylindrical shell as a shock receiving face and can be made expansible and contractible by inflating and deflating it, if necessary, and hence is particularly adapted to be folded and stored in a simple and convenient manner.
Conventional pneumatic marine fender is formed of rubber or rubber-like elastic material and comprises an inner reinforcing layer which is mainly arranged in the following two manners:
(1) Two rubberized cord layers are arranged in axial and circumferential directions of the cylindrical barrel, respectively. PA0 (2) Two rubberized cord layers are inclined at an angle of about 55.degree. and symmetrically arranged with respect to the axial direction of the cylindrical barrel in reverse directions.
In the former conventional pneumatic marine fender, the cords of the circumferentially extending cord layer are joined together to form seams of an endless layer. Such seams have a low tension withstanding ability, and as a result, if the cylindrical barrel is subjected to load, the seams become excessively elongated. As a result, there is a risk of a distance, between adjacent cords of the axially extending cord layer, being enlarged or there is a risk of adjacent rows of the cords of the axially extending cord layer being disturbed, thereby inducing a premature puncture failure of the marine fender. In addition, during shaping of the cylindrical barrel in a vulcanization mold, the elongation at the seams results in an irregular distance between adjacent cords of the axially extending cord layer, thereby making quality of the marine fender irregular.
In the latter conventional pneumatic marine fender, even though it is possible to improve the durability thereof, the energy absorption compressive ability becomes inferior to that of the former conventional pneumatic marine fender.